1071-3rd Chem Exam-1080109(A)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Of the following, __________ has the odor of rotting eggs.
A) NH3 B) H2S C) CO D) NO2 E) HCN
Answer: B
2) Molecular compounds of low molecular weight tend to be gases at room temperature. Which of the following is most likely not a gas at room temperature?
A) Cl2 B) HCl C) LiCl D) H2 E) CH4
Answer: C
3) Which of the following equations shows an incorrect relationship between pressures given in terms of different units?
A) 1.20 atm = 122 kPa
B) 152 mm Hg = 2.03 × 104 Pa C) 0.760 atm = 578 mm Hg D) 1.0 torr = 2.00 mm Hg
E) 1.00 atm = 760 torr Answer: D
4) Of the following, __________ is a correct statement of Boyle's law.
A) PV = constant B) PV = constant C) VP = constant D) VT = constant
E) nP = constant Answer: A
5) A mixture of Xe, Kr, and Ar has a total pressure of 6.70 atm. What is the mole fraction of Kr if the partial pressures of Xe and Ar are 1.60 atm and 2.80 atm, respectively.
A) 0.174 B) 0.256 C) 0.343 D) 0.481 E) 0.570
Answer: C
6) A gas vessel is attached to an open-end manometer containing a nonvolatile liquid of density 0.791 g/mL as shown below.
The difference in heights of the liquid in the two sides of the manometer is 43.4 cm when the atmospheric pressure is 755 mm Hg. Given that the density of mercury is 13.6 g/mL, the pressure of the enclosed gas is __________ atm.
A) 1.03 B) 0.967 C) 0.993 D) 0.990 E) 0.987
Answer: B
7) How many moles of gas are there in a 45.0 L container at 25.0 °C and 500.0 mm Hg?
A) 0.630 B) 6.11 C) 18.4 D) 1.21 E) 207
Answer: D
8) The van der Waals equation for real gases recognizes that __________.
A) gas particles have non-zero volumes and interact with each other B) molar volumes of gases of different types are different
C) the non-zero volumes of gas particles effectively decrease the amount of "empty space" between them D) the molecular attractions between particles of gas decreases the pressure exerted by the gas
E) all of the above statements are true Answer: E
9) The reaction of 50 mL of Cl2 gas with 50 mL of CH4 gas via the equation:
Cl2 (g) + CH4 (g) HCl (g) + CH3Cl (g)
will produce a total of __________ mL of products if pressure and temperature are kept constant.
A) 100 B) 50 C) 200 D) 150 E) 250
Answer: A
10) A tank containing both HF and HBr gases developed a leak. The ratio of the rate of effusion of HF to the rate of effusion of HBr is __________.
A) 4.04 B) 0.247 C) 2.01 D) 0.497 E) 16.3
Answer: C
11) Based on molecular mass and dipole moment of the five compounds in the table below, which should have the highest boiling point?
Substance Molecular
Mass (amu) Dipole Moment (D)
Propane, CH3CH2CH3 44 0.1
Dimethylether, CH3OCH3 46 1.3
Methylchloride, CH3Cl 50 1.9
Acetaldehyde, CH3CHO 44 2.7
Acetonitrile, CH3CN 41 3.9
A) CH3CH2CH3 B) CH3OCH3 C) CH3Cl D) CH3CHO
E) CH3CN Answer: E
12) In liquids, the attractive intermolecular forces are __________.
A) very weak compared with kinetic energies of the molecules B) strong enough to hold molecules relatively close together
C) strong enough to keep the molecules confined to vibrating about their fixed lattice points D) not strong enough to keep molecules from moving past each other
E) strong enough to hold molecules relatively close together but not strong enough to keep molecules from moving past each other
Answer: E
13) Which statements about viscosity are true?
(i) Viscosity increases as temperature decreases.
(ii) Viscosity increases as molecular weight increases.
(iii) Viscosity increases as intermolecular forces increase.
A) (i) only B) (ii) and (iii) C) (i) and (iii) D) none E) all
Answer: E
14) Of the following substances, only __________ has London dispersion forces as the only intermolecular force.
A) CH3OH B) NH3 C) H2S D) Kr E) HCl
Answer: D
15) Of the following, __________ has the highest boiling point.
A) N2 B) Br2 C) H2 D) Cl2 E) O2
Answer: B
16) Which one of the following substances will have hydrogen bonding as one of its intermolecular forces?
A)
B)
C)
D)
E)
Answer: D
17) Which of the following statements is false?
A) The absolute value of the heat of sublimation is equal to the absolute value of the heat of deposition.
B) The heat of sublimation is equal to the sum of the heat of vaporization and the heat of melting.
C) The heat of sublimation is equal to the sum of the heat of vaporization and the heat of freezing.
D) The absolute value of the heat of sublimation is equal to the absolute value of the sum of the heat of condensation and the heat of freezing.
E) The absolute value of the heat of deposition is equal to sum of the absolute value of the heat of vaporization and the absolute value of the heat of freezing.
Answer: C
18) The enthalpy change for converting 1.00 mol of ice at -50.0 °C to water at 70.0 °C is __________ kJ. The specific heats of ice, water, and steam are 2.09 J/g-K, 4.18 J/g-K, and 1.84 J/g-K, respectively. For H2O, Hfus = 6.01 kJ/mol, and Hvap = 40.67 kJ/mol
A) 12.28 B) 6.41 C) 13.16 D) 7154 E) 9.40
Answer: C
19) Which of the following characteristics would prevent liquid crystal behavior?
A) long axial structure B) ionic configuration
C) carbon-carbon single bonds D) double bonding
E) polar groups Answer: B
20) The critical temperature and pressure of CS2 are 279 °C and 78 atm, respectively. At temperatures above 279°C and pressures above 78 atm, CS2 can only occur as a __________.
A) solid B) liquid
C) liquid and gas D) gas
E) supercritical fluid Answer: E
21) In counting the electron domains around the central atom in VSEPR theory, a ________ is not included.
A) nonbonding pair of electrons B) single covalent bond
C) core level electron pair D) double covalent bond
E) triple covalent bond Answer: C
22) The central iodine atom in IF5 has __________ unbonded electron pairs and __________ bonded electron pairs in its valence shell.
A) 1, 5 B) 0, 5 C) 5, 1 D) 4, 1 E) 1, 4
Answer: A
23) For molecules of the general formula ABn, n can be greater than four __________.
A) for any element A
B) only when A is an element from the third period or below the third period C) only when A is boron or beryllium
D) only when A is carbon E) only when A is Xe Answer: B
24) Of the molecules below, only __________ is nonpolar.
A) CO2 B) H2O C) NH3 D) HCl E) TeCl2
Answer: A
25) Molecular Orbital theory correctly predicts paramagnetism of oxygen gas, O2. This is because __________.
A) the bond order in O2 can be shown to be equal to 2.
B) there are more electrons in the bonding orbitals than in the antibonding orbitals.
C) the energy of the 2p MOs is higher than that of the 2p MO
D) there are two unpaired electrons in the MO electron configuration of O2 E) the O O bond distance is relatively short
Answer: D
26) The molecular geometry of the BCl3 molecule is __________, and this molecule is __________.
A) trigonal pyramidal, polar B) trigonal pyramidal, nonpolar C) trigonal planar, polar D) trigonal planar, nonpolar
E) trigonal bipyramidal, polar Answer: D
27) The bond angles marked a, b, and c in the molecule below are about ________, ________, and ________, respectively.
A) 90°, 90°, 90°
B) 120°, 120°, 90°
C) 120°, 120°, 109.5°
D) 109.5°, 120°, 109.5°
E) 109.5°, 90°, 120°
Answer: D
Consider the following species when answering the following questions:
(i) PCl3 (ii) CCl4 (iii) TeCl4 (iv) XeF4 (v) SF6
28) In which of the molecules does the central atom utilize d orbitals to form hybrid orbitals?
A) (i) and (ii) B) (iii) only C) (i) and (v) D) (iii), (iv), and (v)
E) (v) only Answer: D
29) The hybridizations of bromine in BrF5 and of arsenic in AsF5 are __________ and __________, respectively.
A) sp3, sp3d B) sp3d, sp3d2 C) sp3d, sp3 D) sp3d2, sp3d
E) sp3d2, sp3d2 Answer: D
30) Based on molecular orbital theory, the bond orders of the H H bonds in H2, H2+, and H2- are __________, respectively
A) 1, 0, and 0 B) 1, 1/2, and 0 C) 1, 0, and 1/2 D) 1, 1/2, and 1/2
E) 1, 2, and 0 Answer: D
31) __________ solids consist of atoms or molecules held together by dipole-dipole forces, London dispersion forces, and/or hydrogen bonds.
A) Ionic B) Molecular C) Metallic
D) Covalent-network
E) Metallic and covalent-network Answer: B
32) Potassium metal crystallizes in a body-centered cubic structure with a unit cell edge length of 5.31 Å. The radius of a potassium atom is __________ Å.
A) 1.33 B) 1.88 C) 2.30 D) 2.66 E) 5.31
Answer: C
33) The transition metals in group __________ have the highest melting points.
A) 4B B) 3B C) 6B D) 8B E) 2B
Answer: C
34) A category __________ plastic container will generally be the most easily recycled.
A) 1 B) 2 C) 3 D) 4 E) 22
Answer: A
35) Blue LEDs are usually made of __________.
A) GaAs B) GaP C) GaO D) GaS E) GaN
Answer: E
36) NaCl crystallizes in a face-centered cubic cell. What is the total number of ions (Na+ ions and Cl- ions) that lie within a unit cell of NaCl?
A) 2 B) 4 C) 8 D) 6 E) 5
Answer: C
37) The process of doping can produce a __________ which can greatly __________ intrinsic conductivity.
A) n-type semiconductor, increase B) p-type semiconductor, decrease C) non-metal, increase
D) non-metal, decrease E) allotrope, diminish Answer: A
38) 12 karat gold contains __________% gold.
A) 12 B) 25 C) 5.0 x 101 D) 75 E) 1.0 x 102
Answer: C
39) As a polymer becomes more crystalline, __________.
A) its melting point decreases B) its density decreases C) its stiffness decreases D) its yield stress decreases
E) None of the above is correct.
Answer: E
40) CsCl crystallizes in a unit cell that contains the Cs+ ion at the center of a cube that has a Cl- at each corner.
Each unit cell contains __________ Cs+ ions and __________ Cl-, ions, respectively.
A) 1 and 8 B) 2 and 1 C) 1 and 1 D) 2 and 2 E) 2 and 4
Answer: C
